An international team led by Tang Xindi from Xinjiang Astronomical Observatory (XAO) of the Chinese Academy of Sciences (CAS), collaborating with Christian Henkel from Max Planck Institute for Radioastronomy in Germany, revealed that the gas heating of star forming region in the Large Magellanic Cloud (LMC) by using the Atacama Large Millimeter/submillimeter Array (ALMA).
The Large Magellanic Cloud at a distance of 50 kpc is the nearest low-metallicity star-forming galaxy to the Milky Way. In the LMC, the far-ultraviolet (FUV) field is stronger than in the Milky Way while metallicities are lower. It is thus well suited for studying the properties of the interstellar medium, the evolution of molecular clouds, and star formation in a small nearby active galaxy, which provides a direct link to galaxies at high redshift.
The researchers mapped the kinetic temperature structure of two massive star-forming regions, N113 and N159W, in the LMC making use of the 1.3 mm H2CO transitions with the ALMA. They found the kinetic temperatures of the dense gas traced by H2CO are weakly affected by the external sources of the Hα emission. The gas heating for the dense gas of star-forming regions in low metallicity environments with strong UV radiation in the LMC may be dominated by internal star formation activity, radiation, and/or turbulence. It seems that the mechanism heating the dense gas of the star-forming regions in the LMC is consistent with that in Galactic massive star-forming regions located in the Galactic plane. The physical and chemical processes of dense gas on a scale of 0.4 pc in star-forming regions of the LMC might be different from those in low density regions, so the very dense gas clouds should not be simply modeled as photon dominated regions in low metallicity environments.
